1 Field of Invention
This invention relates to services offered to application providers and subscribers of mobile networks. In particular, the invention pertains to access methods for mobile networks.
2 Description of Prior Art
Mobile networks support large numbers of mobile subscribers who are able to receive services on the move. These include basic services such as voice calls, and they also include more advanced services such as Internet access, mobile commerce, location based content delivery, etc. A mobile network typically maintains the dynamic network state, including location and presence, of millions of mobile subscribers. In order to support this large number of mobile subscribers, existing mobile networks are divided into a number of separate operational entities called Public Land Mobile Networks (PLMN). Typically, the coverage area of a PLMN is confined within the boundaries of a single country. Also, a single country may have many PLMNs with overlapping coverage areas. A mobile subscriber typically subscribes to a single PLMN. The specific PLMN is called the home PLMN of the subscriber. The subscriber may also obtain mobile services from other PLMNs (called visited PLMN) while on the move. This involves communication between the visited PLMN and the home PLMN of the subscriber.
In order to route calls and services to mobile subscribers, a mobile network must memorize for each subscriber whether she is known to be in some place or not (registered with the network), and if so, the location area (including the PLMN) where she is currently located. This is achieved by storing in a database the identity of each mobile subscriber together with an indication on whether or not she is registered, and if so, where the subscriber can be found. The Home Location Register (HLR) in the home PLMN of the mobile subscriber is such a database. In addition to storing the dynamically changing network state of the mobile subscriber, the HLR is also the repository for some relatively static information for the subscriber, such as subscribed services, authentication parameters etc. Another mobile network database is responsible for temporarily maintaining subscriber information (both static and dynamic) in order to reduce network signaling by keeping it close to the subscriber when the subscriber is roaming. This database is the Visited Location Register (VLR). Subscriber data is kept synchronized between the HLR and the VLR by exchange of mobility messages.
In order to support location based emergency services, mobile networks are being enhanced to provide subscriber location information accurate to within several meters. This information is also being utilized for providing location-based services to mobile subscribers, where, based on their location, highly relevant local content is made available, such as information about nearby shops and restaurants, etc. The location enabling entities in a mobile network conventionally include Location Measurement Units (LMU) or Position Determination Equipment (PDE) that provide measurements regarding a mobile station""s (subscriber""s) current location. A Serving Mobile Location Center (SMLC) controls the overall location procedure for each mobile station by instigating location-related measurements. The SMLC computes mobile station (subscriber) position from the resulting measurements and returns the final location estimate to the requesting entity. A Gateway Mobile Location Center (GMLC) supports interfaces to external clients to provide to them the mobile station""s position. The GMLC itself interfaces with the HLR and the VLR to determine the current SMLC for the mobile station, and uses that SMLC to obtain the location estimate for the subscriber.
Mobile network operators are beginning to realize that the dynamic state of mobile subscribers within mobile networks is a highly valuable resource that can be tapped to provide value-added services. However, much of this resource is located deep within the networks and is distributed within closed and propriety network elements, making it virtually impossible for new services that access the resource to be built rapidly and effectively. Motivated by the potential windfall to be obtained by permitting access to mobile subscriber dynamic state information, mobile network operators are beginning to open up their networks by making interfaces into the network elements (e.g., GMLCs, HLR/VLR) available to entities that may host third party applications. Standards bodies such as LIF (Location Interoperability Forum) and 3GPP (3rd Generation Partnership Project) are getting involved in formulating standards for these interfaces to the network elements, including GMLCs and HLR/VLRs. It is thus now becoming possible for external entities to query mobile networks to obtain the dynamic network state of the mobile subscribers.
One of the biggest concerns that mobile network operators have regarding opening up their networks, is the potential impact on existing services that form the core revenue source for such entities. They are concerned, for example, that a rogue application may inundate the mobile networks with user status queries, thereby bringing the core network services to a grinding halt where not even standard voice services can be supported.
The invention address the foregoing concerns by providing a method and system for obtaining the dynamic network state of mobile subscribers, such as subscriber location, presence, or other state information. This information, which may be distributed within various core mobile network elements, can be obtained via a differentiated network service gateway (DNSG) that interfaces with the mobile network elements in a manner that accommodates the mobile network""s operator enforced controls and limitations. To that end, the DNSG implements service level agreements (SLAs) that support differentiated quality-of-service (QoS) in terms of accessing the dynamic network state of the mobile subscribers. The consumers (DNSG clients) of the dynamic network state information may include applications that provide communication and transactional services to mobile subscribers based on their dynamic network state, and the mobile subscribers themselves. These consumers register with the DNSG for SLAs to obtain a desired QoS that determines the precision and speed at which the network service functions for their exclusive use. The DNSG uses the SLAs to allocate available server resources to the consumers and for scheduling queries to the core network elements so as to obtain mobile subscriber dynamic network state information according to the requirements of all of the SLAs.